Study On The Isolation And Insecticiadal Activities Of Chemical Constituents From Tephrosia Purpurea Leaves

Tephrosia purpurea, mostly distributed in subtropical areas, is a copiously branched perennial herb. The whole plant is toxic especially the root and has rich resources. As a traditional medicine, T. purpurea was also used as a green manure, but little was reported on the insecticida activity. Our previous studies had revealed the methanol extract from the leaves of T. purpurea possessed insecticidal property, in this study we took the leaves as materials, researched their chemical compositions and insecticiadal activities to learn their active substance basis.In order to obtain the methanol extract of the T. purpurea leaves, the leaves were soaked in methanol at room temperature, and then the solvent was concentrated under reduced pressure. With the methods of column chromatography (normal and reversed phase silica gel, Sephadex LH-20), preparative TLC and HPLC, seventeen compounds were isolated. On the basis of spectroscopic methods including UV, ID,2D NMR and HR-ESR-MS, the structures of these compounds were elucidated as stigmast-1,5-dien-3β-ol (1), clemaphenol A (2),(+)-pinoresinol (3), eudesmin (4), indole-3-carbaldehyde (5), tryptophan (6),(S)-4-benzyl-2-oxazolidinone (7),4-hydroxybenzene propanoic acid (8), buteaspermanol (9), obovatachalcone (10), pongachin (12),5,7-dimethoxy-8-(3-hydroxy-3-methylbut-lZ-enyl)flavanone (13),6-methoxykaempferol (3,4’,5,7-tetrahydroxy6-methoxy flavone)(14),6-methoxykaempferol7-O-a-rhamnopyranoside (15),6-methoxykaempferol3-O-α-rhamnopyranosyl(1→2)[a-rhamnopyranosyl(1→6)]-β-galactopyranoside (16),6-methoxykaempferol3-O-α-rhamnopyranosyl(1→2)[α-rhamnopyranosyl(1→6)]-β-galactopyranoside-7-O-a-rhamnopyranoside (17). Compound1was a sterol, compounds2-4were lignanoids, compounds5-7were nitrogen-containing compounds, compound8was an acid, the compounds9,12-17were flavonoids, compounds10and11were chalcones. Except compounds3,6,10,12, all the other compounds were first isolated from T. purpurea. Compounds1,12,14-17were produced with large quantity while others were few.We also described the cytotoxicitives against the ovarian cells from Sprodenia litura(SI cells) of the seventeen compounds with MTT test. The results showed that compounds1-17against SL cells were arranged in the following order from high to low:12<6<14<16<rotenone<15<17<13, with the IC50values of4.4,12.2,27.8,78.8,108.0,134.1,189.7,250.0(mg/L). Compounds6and12had significant activity while compounds14and16, whose cytotoxicity exceeded rotenone, also showed moderate activity. Compounds1,2,3,7,8,13,17showed no cytotoxicitives. The cytotoxicity values of compounds12,4,14,16were discussd and evaluated.